Commutator.



No. 832,353. PATENTED OCT. 2, 1906.

R. S. WHITE.

COMMUTATOR.

APPLICATION FILED 0011.14. 1902.

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Inventor.

Roger S.White, MM-

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No. 832,353. PATENTED OCT. 2; 1906,

R. S. WHITE.-

GOMMUTATOR.

APPLICATION TILED 001'. 14. 1902.

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. UNITED STATES PATENT OFFICE.

ROGER S. WHITE, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO.

GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK. I

COMMUTATOR.

Specification of Letters Patent.

Patented Oct. 2, 1906.

Application filed October 14, 1902. Serial No. 12'7,229.

T0 aZZ whmn it may concern:

Be it known that I, ROGER S. WVHITE, a citizen of the United States,residing at Philadelphia, county of Philadelphia, State of Pennsylvania,have invented certain new and useful Improvements in Commutators, ofwhich the following is a specification.

My invention relates to new and useful improvements in the constructionof commu tators and of roller-collectors for electric-motor meters, andis especially adapted to those having an armature mounted on ahorizontal shaft supported by roller-bearings which also cooperate withthe commutator and act as current-collectors. Heretofore in motors ofthis type commutators have been used having the usual straight-edgesegment, rendering it necessary to make the gaps or airspaces betweenthe segments as small as possible, as each gap, forming, in effect, aflattened surface, breaks the continuity of the true circular path ofcontact on the commutator-surface of the roller-bearings and allows thearmature to settle a minute distance as each gap passes a roll. This ismore particularly noticeable with a very small load and introduces anerror which, while almost negligible when a very light armature isemployed and when the commutatorsegments are very near together, becomesserious when an armature of heavier construction is used, as inwattmeters or large-capacity instruments, and when higher differences ofpotential between adjoining segments having an increased air-gap isdesired. Now in order to eliminate this source of error I employ anewand improved commutator and roll by means of which I secure and maintainan even, true, and constant condition of contact of commutator andcollecting device. I provide two pairs of rollers on which thecommutator of the meter-motor bears, each pair being connected to oneside of the line and taking the place of a single brush, and I soconstruct the parts that one roller of each pair is slightly ahead ofthe other roller of that pair relatively to the segments of thecommutator. I accomplish this by mounting the two rollers of each pairon the same shaft and forming the commutatonsegments so that they extendaround the cylindrical surface of the commutator enough to make eachsegment overlap the next. For this purpose the segments may be curvedhelically commutator.

throughout their length, or, as I prefer to make them, one-half of eachsegment may be ofi'set relatively to the other half so as to be slightlyin advance of it on the surface of the As thus constructed thecommutator rests on the two pairs of rollers which constitute theantifrictionbearing for one end of the shaft, the two rollers of eachpair being of the same size and mounted to engage the commutator onopposite sides of the ofl'set in the segments. If segments'are usedwhich are curved throughout their length, the rollers of each pair aremounted a sufficient distance apart to have the same effect. It willthus be seen that one roller of each pair is slightly in advance of theother roller of that pair relatively to the commutatorsegments, and I soarrange the parts that this advance is sufficient to bring one rollerinto contact with a segment as the commutator is turned on its axis justbefore the other roller of that pair breaks contact with the adjacentsegment. As the two rollers of each pair are electrically connected, acoil of the armature is thus short-circuited momentarily when thecurrent therein is reversed. Also the slight drop or lateral movement ofthe shaft and armature when a segment leaves the roller is prevented, asone roller of each pair is always in engagement with a segment, and thussupporting the shaft in proper position. "Moreover, there are two pathsfor the current entering and leaving the commutator, thus affordingbetter electrical connections to the coils of the armature.

The features of novelty of my invention will be definitely indicated inthe appended claims.

The details of construction and the mode of operation will be betterunderstood by reference to the accompanying drawings, which show oneembodiment "of my invention.

In the accompanying drawings, Figure 1 is an end view of a commutatorembodying my invention. Fig. 2 is a side elevation of the same, showinga single commutator and set of rolls. Fig. 3 is an end view of a modification.

View of the preferred shape of commutatorsegment. Fig. 8 is an end viewof the same.

Fig. 4 is a side elevation of the, same, showing two commutators eachwith' Fig. 9- is an end view of the same bent to the desired curvature.Fig. 10 shows the assembled commutator. Fig. 11 is an end view thereof.roll in proximity to the commutator. Figs. 13, 14, and 15 illustratevarious modified forms of segments, and Fig. 16 shows a roll in whichthe contact portions are insulated from the shaft;

Let 1 represent the armature-shaft of the motor-meter, preferablysupported in a horizontal position either on a conical bearing 2 at oneend and a roller-commutator 3 at the other, as'shown in Fig. 2, or onroller-commutators at both ends, as shown in Fig. 4. The preferred shapeof commutator-segment is shown in Figs. 2, 4, 7, and 10, where theortion a. b of one edge of the segment 4 overaps a slight distancebeyond the theoretical line of commutation X Y, while the remain- .ingportion 0 d of the same edge does not eX- tend to said line. Theopposite edge of said segment is similarly stepped, the portion 0 f,corresponding to and parallel with the pore tion a b, stopping short ofthe line of commutation- X Y, while the portion 9 h, correspondin to andparallel with the portion a (1, over aps said line by the same amount asthe ortion a b overlaps the line X Y. It is rea y necessary that theseedges a b, g h shou d extend only to the theoretical line ofcommutation; but by overlapping them a little less accuracy isreguisitein shaping the segments and in assemb ing the commutator.

The segments are preferably punched from sheet metal and arethen curved,as shown in Fig. 9, to fit the periphery of the body or spool 5 ofinsulation. The heads of the spools have equispaced notches 6 to receivetongues 7 on the segments, which are then clam ed in place by rings 8.

The ro s which support the commutator and serve to convey current to thearmature the disk 9 only.

each comprise two parallel metal disks 9 9" of the same diameter mountedon a shaft 10. Ordinarily both disks support the commutator, beingso'arranged that the edges a b, e f pass over one disk and the portions0 d, g h over the other. Suppose the commutator shown in Fig. 10 to berotating. It is evident that when the gaps adjoining the edges 0 d, g itpass the disk 9' the other disk 9 alone sup:

ports the commutator, and when in turn the gaps adjoining the edges a b,e f reach the disk 9 the commutator will be supported by In eachinstance the supporting-disk will engage a cylindrical portion of asegment, so that there will be no jolt as V the gaps pass the otherdisk.

It is obvious that many other shapes of commutator-segment may be used.Thus in Fi 13 there are two steps, in Fig. 14 a plura it of small stepshaving square edges, and in ig. 15 a plurality of V-shaped steps.

12 shows a double-disk With segments of such shapes the number andrelative position of the disks must be modified to correspond. Indeed,with Figs. 14 and 15 a cylindrical roller extending the full length ofthe commutator may be used. It is obvious, also, that flat brushes maybe used in conjunction with my improved meter-commutator with markedadvantage. In the case of brush and commutator contact as in ordinaryuse it is found that it constitutes by far the largest frictionfactor inmeters, especially marked as a ap-is passing a brush, for the recedingedge 0 one segment a llowsthe brush in contact with it to drop until theapproaching edge of the next segment comes in contact with and raises itto its normal position. In doing this, however, it

not only lifts the brush against the force of- I its spring, but it doesso with its more or The armature-shaft may have more than one armature,and they may be arrangedjn several diflerent ways and connected up indifferent electrical circuits, as will be apparent to. any one skilledin the art. If it is desired to use an insulated roller-bearing, I

the disks may be insulated from the shaftby an insulating-sleeve 11, asshown. in .Fig. 16. 'i What I claimasnew, and desireto secure by LettersPatent of the United States, is'

1. An electrical instrument comprising an armature-shaft, a commutatorhaving overlapping segments carried thereby, and pairs ofcurrent-carrying rollers supporting said commutator.

2. In an electrical instrument, a shaft, an armature and commutatorcarried thereby, and two pairs of coaxial rollers on which saidcommutator bears, said commutator being so constructed and arranged thatone roller of each pair is in advance of the other of that pairrelatively to the segments of the commutator.

3. An electrical instrument comprising a shaft and armature, acommutator having overlapping segments carried by said shaft, and a pairof current-carrying rollers arranged so that one of the rollers passesthe gap between adjacent segments before the other roller.

4. In an electrical instrument, a shaft, an

' armature and commutator carried thereby,

and pairs of concentric rollers on which said commutator bears, saidcommutator and rollers beingarranged to short-circult coils of thearmature successively and to prevent jarring of the shaft as thesegments of the commutator leave the rollers.

5. In an electrical instrument, a shaft, an armature carried thereby, acommutator on said shaft having segments which overlap longitudinally ofthe commutator, and current-carrying bearing-rollers for supporting saidcommutator.

6. In an electrical instrument, a shaft, an armature carried thereby, acommutator on said shaft, a portion of each segment of the commutatorbeing in advance of the remainder of the segment circumferentially ofthe commutator, and current-carrying bearing-rollers for supporting saidcommutator.

7. In an electrical instrument, a shaft, an armature and commutatorcarried thereby, each segment of said commutator having an offsettherein advancing a part of the segment ahead of the remaindercircumferentially of the commutator, and a pair of rollers mounted tomake electrical contact with and support the segments of the commutatoron opposite sides of said ofisets.

8. In an electrical instrument, a shaft, an

armature and commutator carried thereby, each segment of said commutatorhaving an offset therein advancing a part of the segment ahead of theremainder circumferentially of the commutator, and two pairs of rollerson which the commutator bears, the rollers of each pair being arrangedto contact with the several segments of the commutator on opposite sidesof the offsets.

9. In an electrical instrument, a shaft, an armature and commutatorcarried thereby, each segment of said commutator having an ofisettherein advancing a part of the segment ahead of the remaindercircumferentially of the commutator, and two pairs of rollers on whichsaid commutator bears, the rollers of each pair being electrically connected and arranged to contact with the commutator-segments on oppositesides of said offsets.

In witness whereof I have hereunto set my hand this 11th day of October,1902.

ROGER S. WHITE. [L. s.] WVitnesses:

EDMUND JoNEs, A. STANLEY PETERSON.

